`1/{3.4} - 1/{4.5} - 1/{5.6} - 1/{6.7} - 1/{7.8} - 1/{8.9}`
`= 1/{3.4} - (1/{4.5} + 1/{5.6} + 1/{6.7} + 1/{7.8} + 1/{8.9})`
`= 1/{3.4} - (1/4 - 1/5 + 1/5 - 1/6 + 1/6 - 1/7 + 1/7 - 1/8 + 1/8 - 1/9)`
`= 1/{3.4} - (1/4 - 1/9)`
`= (1/3 - 1/4) - (9/36 - 4/36)`
`= (4/12 - 3/12) - 5/36`
`= 1/12 - 5/36`
`= 3/36 - 5/36`
`= -2/36`
`= -1/18`